Question

एक मोमबत्ती की लौ का उत्तल लेंस द्वारा एक पर्दे पर प्रतिबिंब बनायें। लेंस से मोमबत्ती की लौ की
दूरी बदल कर प्रतिबिंब के आकार और प्रकृति का अध्ययन करें।
Obtain the image of a candle flame made by a convex lens on a screen. Study
the nature and size of the image for different distances between the candle
flame and the lens.
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Answer 1

A convex lens form a real and diminished image for objects placed beyond its focal length and forms a virtual magnified image for objects closer that its focal length.

1. Consider object at infinity.

• Then the lens forms real image at the focus .
• It will be a point image

    2. Consider object beyond 2f.

• Then the image will be real and between f and 2f.
• It will be smaller than the object.

    3. Consider the object between f and 2f

• The image will be real and beyond 2f.
• It will be an enlarged image.

    4. Consider the object at f

• The image will be real and formed at infinity.
• It will be an enlarged image.

    5. Consider the object between the lens and within f.

• Image will be virtual and enlarged and on the same side of the lens as the object.